METHOD FOR FORMING CONDUCTIVE PATTERN BY DIRECT RADIATION OF ELECTROMAGNETIC WAVE, AND RESIN STRUCTURE HAVING CONDUCTIVE PATTERN THEREON (As Amended)

ABSTRACT

Provided are a method for forming conductive pattern by direct radiation of an electromagnetic wave capable of forming fine conductive patterns on various kinds of polymer resin products or resin layers by a simplified process, even without containing specific inorganic additives in the polymer resin itself, and a resin structure having the conductive pattern formed thereon. 
     The method for forming the conductive pattern by direct radiation of the electromagnetic wave includes: forming a first region having a predetermined surface roughness by selectively radiating the electromagnetic wave on a polymer resin substrate; forming a conductive seed on the polymer resin substrate; forming a metal layer by plating the polymer resin substrate having the conductive seed formed thereon; and removing the conductive seed and the metal layer from a second region of the polymer resin substrate, wherein the second region has surface roughness smaller than that of the first region.

TECHNICAL FIELD

The present invention relates to a method for forming conductive patternby direct radiation of an electromagnetic wave capable of forming fineconductive patterns on various kinds of polymer resin products or resinlayers by a simplified process, even without containing specificinorganic additives in the polymer resin itself, and a resin structurehaving the conductive pattern formed therefrom.

BACKGROUND ART

In recent years, as a fine electronic technology is developed, demandfor a structure in which fine conductive patterns are formed on asurface of polymer resin substrates (or products) of various kinds ofresin products or resin layers, and the like has been increased. Theconductive patterns on the surface of the polymer resin substrate andthe structure may be applied to form various targets such as antennasintegrated into a cellular phone case, various kinds of sensors, MEMSstructures, RFID tags, and the like.

In particular, recent portable devices such as a smart phone, and thelike, need to have simultaneously mounted local area network functionssuch as communication, bluetooth, Wi-Fi, electronic payment, and thelike, unlike the existing cellular phone, and the like, and due to thisreason, it is required to simultaneously mount various antennas in onesmart phone. However, since aesthetic design aspect of the portabledevices such as the smart phone, and the like, in addition thereto, isemphasized, a method for forming conductive pattern capable of servingas various antennas on the surface of the polymer resin substrate suchas the case of the portable devices, and the like, has been continuouslysuggested and researched so as to simultaneously meet these demands.

As the interest in the technology of forming conductive patterns on thesurface of the polymer resin substrate has been increased, severaltechnologies regarding this were suggested. For example, a method forforming conductive pattern on a polymer resin substrate by blending andmolding specific inorganic additives containing transition metals suchas copper, chrome, and the like, (for example, CuCr₂O₄ having the spinelstructure, and the like} in a polymer resin chip to form a polymer resinsubstrate, directly radiating an electromagnetic wave such as a laser,and the like, on a predetermined region, and plating the laser radiatedregion to form a metal layer was suggested. In this method, theinorganic additive-derived components in the laser radiated region areexposed and function as a seed for a kind of plating, such that themetal layer and conductive patterns may be formed.

However, since a substantial amount of high priced and specificinorganic additives should be used in the method for forming theconductive pattern, there is a disadvantage in that the totalmanufacturing cost is increased. In addition, since the inorganicadditive needs to be blended into the polymer resin chip itself, theinorganic additive may deteriorate physical properties such asmechanical properties, and the like, of the polymer resin substrate orresin products formed therefrom. Further, the specific inorganicadditives such as CuCr₂O₄ having the spinel structure, and the like,have significantly dark color itself, such that the specific inorganicadditives may be deteriorating factors in implementing the polymer resinsubstrates or the resin products containing the specific inorganicadditives with colors desirable to consumers. For example, in order toimplement the polymer resin substrate containing the inorganic additivesto have desirable colors, a large amount of pigment should be used, andit is not easy to implement white color.

Due to the disadvantages, a technology capable of forming fineconductive patterns by a simplified process on various kinds of thepolymer resin products or the resin layers even without containing thespecific inorganic additives in the polymer resin itself has beendemanded.

SUMMARY OF INVENTION Technical Problem

The present invention provides a method for forming conductive patternby direct radiation of an electromagnetic wave capable of forming fineconductive patterns on various kinds of polymer resin products or resinlayers by a simplified process, even without containing specificinorganic additives in the polymer resin itself.

In addition, the present invention provides a resin structure having theconductive pattern obtained by the method of forming the conductivepattern.

Solution to Problem

An exemplary embodiment of the present invention provides a method forforming conductive pattern by direct radiation of an electromagneticwave, the method including: forming a first region having apredetermined surface roughness by selectively radiating theelectromagnetic wave on a polymer resin substrate; forming a conductiveseed on the polymer resin substrate; forming a metal layer by platingthe polymer resin substrate having the conductive seed formed thereon;and removing the conductive seed and the metal layer from a secondregion of the polymer resin substrate, wherein the second region hassurface roughness smaller than that of the first region.

In addition, the surface roughness of the first and second regions maybe defined by other methods. For example, when a cross-cut test havingan interval of 2 mm or less according to ISO 2409 standard method isconducted by using a tape having adhesion of 4.0 to 6.0N/10 mm width,the first region of the polymer resin substrate may have a surfaceroughness defined by adhesion at which a delamination area of a targetmetal layer under test corresponds to about 5% or less of an area of themetal layer, and when the same test is conducted on the remaining secondregion, the remaining second region of the polymer resin substrate mayhave a surface roughness defined by adhesion at which a delaminationarea of the target metal layer under test corresponds to 65% or more ofan area of the metal layer.

Another exemplary embodiment of the present invention provides a resinstructure having conductive pattern including: a polymer resin substrateincluding a first region formed to have a predetermined surfaceroughness and a second region having surface roughness smaller than thatof the first region; and a conductive seed and a metal layer selectivelyformed on the first region of the polymer resin substrate.

Advantageous Effects of Invention

According to the present invention, even though high priced and specificinorganic additives such as CuCr₂O₄ having a spinel structure, and thelike, are not contained in a polymer resin substrate itself, surfaceroughness and adhesion to a metal layer, of a region in which conductivepatterns are formed by radiating an electromagnetic wave such as laser,or the like, may be adjusted, such that the conductive patterns may beformed on the polymer resin substrate by a simplified process.

Therefore, the manufacturing cost of the process of forming theconductive patterns may be decreased, and deterioration of physicalproperties such as mechanical properties, dielectric constant, and thelike, of the polymer resin substrate or products caused by the specificinorganic additive, a high power electromagnetic wave radiation, or thelike, may be minimized. In addition, since desirable fine conductivepatterns may be formed on the polymer resin substrate without using thespecific inorganic additive, colors of the resin itself may be clearlyshown, and it is easy to implement colors of the polymer resin substrateor products to be desirable colors.

Therefore, by using the method for forming the conductive pattern,conductive patterns for antenna, RFID tags, various kinds of sensors,MEMS structures, and the like, may be significantly effectively formedon various kinds of resin products such as a smart phone case, and thelike.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram schematically showing one example of a method forforming conductive pattern by directly radiation of an electromagneticwave according to an exemplary embodiment of the present invention in aprocess-sequence.

FIG. 2a shows a photograph showing a state in which a predeterminedregion has surface roughness by radiating laser to the polymer resinsubstrate (first photograph), a photograph showing a state in which acopper metal layer is formed by electroless plating after radiatinglaser (second photograph), and a photograph showing a state in whichplating layers are removed from the remaining region which is notradiated by laser, by selective delamination or removal after theelectroless plating (third photograph), in the method for forming theconductive pattern of Example 1.

FIG. 2b is an optical microscope photograph of the laser radiated regionhaving surface roughness according to Example 1.

FIG. 2c is a scanning electron microscope (SEM) photograph showing aportion in which the metal layer (conductive patterns) is formed inExample 1, wherein a conductive seed is grown, and the metal layer isformed on the conductive seed by plating.

FIG. 3 is a photograph showing a state in which the conductive patternsare formed on the polymer resin substrate by selectively removing themetal layer, and the like, from the region which is not radiated bylaser in the method for forming the conductive pattern of Example 9.

FIG. 4a is a photograph showing color change depending on height usingoptical profiler in the laser radiated region of Example 6 (left), andis a photograph showing the color change in three dimensional structure(right).

FIG. 4b is a photograph showing color change depending on height usingoptical profiler in the laser radiated region of Example 8 (left), andis a photograph showing the color change in three dimensional structure(right).

DESCRIPTION OF EMBODIMENTS

Hereinafter, a method for forming conductive pattern by direct radiationof an electromagnetic wave according to a specific exemplary embodimentof the present invention, and a resin structure having the conductivepatterns formed therefrom will be described.

According to an exemplary embodiment of the present invention, themethod for forming conductive pattern by direct radiation of anelectromagnetic wave, the method including: forming a first regionhaving a predetermined surface roughness by selectively radiating theelectromagnetic wave on a polymer resin substrate; forming a conductiveseed on the polymer resin substrate; forming a metal layer by platingthe polymer resin substrate having the conductive seed formed thereon;and removing the conductive seed and the metal layer from a secondregion of the polymer resin substrate, wherein the second region hassurface roughness smaller than that of the first region.

According to the exemplary embodiment of the present invention, first, asurface structure having a shape such as concavo-convex, predeterminedpatterned, amorphous shape, or the like, is formed so that a polymerresin substrate of the first region has a predetermined surfaceroughness by radiating an electromagnetic wave such as laser, or thelike, on a first region in which the conductive patterns are formed. Inthe first region, adhesion between a surface of the polymer resinsubstrate and a metal layer to be formed by plating in the first regionmay be improved due to the predetermined surface roughness.

Meanwhile, in a second region which is not radiated by theelectromagnetic wave such as laser, or the like, poor adhesion betweenthe surface of the polymer resin substrate and the metal layer in thesecond region may be shown due to original surface property of thepolymer resin substrate itself.

Accordingly, when a conductive seed for facilitating a plating processis formed on the polymer resin substrate of the first region and theplating process is performed, the metal layer having excellent adhesionwith the polymer resin substrate may be favorably formed on the firstregion; meanwhile, the metal layer which is easily removed due to pooradhesion may be formed on the second region. Therefore, when weakphysical power is applied to the polymer resin substrate to selectivelyremove the metal layer and the conductive seed of the second region,desired conductive patterns may be easily formed on the polymer resinsubstrate.

As described above, according to an exemplary embodiment of the presentinvention, for example, even though high priced specific inorganicadditives such as CuCr₂O₄, and the like, having the spinel structure arenot contained in the polymer resin substrate itself, surface roughness,adhesion, and the like, of the region in which the conductive patternsare formed by radiating the electromagnetic wave such as laser, or thelike, may be adjusted, such that the conductive patterns may be formedon the polymer resin substrate by a simplified process.

Therefore, the manufacturing cost of the process of forming theconductive patterns may be decreased, and deterioration of physicalproperties such as mechanical properties, and the like, of the polymerresin substrate or products caused by the specific inorganic additive,may be minimized. In addition, since desirable fine conductive patternsmay be formed on the polymer resin substrate without using the specificinorganic additive, colors of the resin itself may be clearly shown, andit is easy to implement colors of the polymer resin substrate orproducts to be desirable colors.

Meanwhile, hereinafter, the method for forming the conductive pattern bydirect radiation of an electromagnetic wave according to an exemplaryembodiment of the present invention is more specifically described foreach process step with reference to drawings. FIG. 1 is a diagramschematically showing one example of a method for forming conductivepattern by direct radiation of an electromagnetic wave according to anexemplary embodiment of the present invention in a process-sequence.

As shown in {circle around (1)} and {circle around (2)} of FIG. 1, inthe method for forming the conductive pattern according to an exemplaryembodiment, the first region having a predetermined surface roughness isfirstly formed by selectively radiating an electromagnetic wave on thepolymer resin substrate.

The polymer resin substrate may be formed by using any thermosettingresin or any thermoplastic resin. Specific examples of the polymerresins capable of forming the polymer resin substrate such as thethermosetting resin or the thermoplastic resin may include an ABS resin,a polyalkylene terephthalate resin such as a polybutylene terephthalateresin, a polyethylene terephthalate resin, or the like, a polycarbonateresin, a polypropylene resin, a polyphthalamide resin, and the like, andin addition thereto, the polymer resin substrate may be formed by usingvarious polymer resins.

In addition, the polymer resin substrate may be formed of theabove-described polymer resin; however, may further contain additives,for example, an UV stabilizer, a heat stabilizer, or an impactreinforcing agent, generally used to form the polymer resin product, asneeded. The additives may be contained in an appropriate amount of about2 wt % or less, or about 0.01 to 2 wt %, based on the weight of thetotal polymer resin substrate. Meanwhile, the polymer resin substratedoes not have to include the specific inorganic additives such asCuCr₂O₄ having a spinel structure, and the like, used to form theconductive patterns by radiating the electromagnetic wave which areknown in the art.

Meanwhile, the first region has a predetermined surface roughness byradiating an electromagnetic wave such as laser, or the like, on theabove-described polymer resin substrate, wherein in the first regionhaving the surface roughness, relatively standardized patterns such ashole, mesh pattern, or the like, or concavo-convex shapes may be formed,or amorphous surface structure in which a plurality of irregular holes,patterns, or concavo-convex are complexly formed may be formed, and thepolymer resin substrate of the first region may have a predeterminedsurface roughness due to the various surface shapes or structures.

As an example, in order to secure excellent adhesion between the metallayer (conductive patterns) to be formed in the first region and thesurface of the polymer resin substrate, the first region of the polymerresin substrate may have surface roughness defined by a center linearithmetic average roughness of the absolute values (Ra) of about 500 nmor more, or about 1 μm or more, or about 1 to 3 μm, and the secondregion which is not radiated by the electromagnetic wave may havesurface roughness defined by a center line arithmetic average roughnessof the absolute values (Ra) having surface roughness smaller than thatof the first region, for example, about 400 nm or less, or about 100 nmor less, or about 0 to 90 nm.

In addition, the above-described surface roughness may also be definedby other methods. For example, the surface roughness of the first andsecond regions may be defined by degree of adhesion to the metal layermeasured in a cross-cut test according to ISO 2409 standard method. Forexample, when a cross-cut test having an interval of 2 mm or lessaccording to ISO 2409 standard method is conducted by using a tapehaving adhesion of 4.0 to 6.0N/10 mm width, the first region of thepolymer resin substrate may have a surface roughness defined by adhesion(for example, ISO class 0 or 1) in which a delamination area of thetarget metal layer under test corresponds to about 5% or less of an areaof the metal layer, and when a cross-cut test having an interval of 2 mmor less according to ISO 2409 standard method is conducted by using atape having adhesion of 4.0 to 6.0N/10 mm width, the second region ofthe polymer resin substrate may have a surface roughness defined byadhesion (for example, ISO class 5 or more) in which a delamination areaof the target metal layer under test corresponds to 65% or more of anarea of the metal layer.

As the polymer resin substrate of the first region has theabove-described surface roughness by radiating the electromagnetic wavesuch as laser, or the like, when the metal layer is formed on the firstregion in the following plating process, thee metal layer may be formedand maintained on the polymer resin substrate with excellent adhesion,to form excellent conductive patterns. As compared to the first region,as the polymer resin substrate of the second region which is notradiated by an electromagnetic wave such as laser, or the like, has theabove-described surface roughness due to surface property itself, whenthe metal layer is formed in the following plating process, the secondregion may have significantly low adhesion to be easily removed. As aresult, the metal layer of the second region may be easily andselectively removed to form the conductive patterns on the polymer resinsubstrate of the first region.

Meanwhile, an electromagnetic wave such as laser, or the like, may beradiated under predetermined conditions as described below so that thepolymer resin substrate of the first region has the above-describedsurface roughness.

First, in the radiating of the electromagnetic wave, laserelectromagnetic wave may be radiated, for example, laser electromagneticwave having a wavelength of 248 nm, about 308 nm, about 355 nm, about532 nm, about 585 nm, about 755 nm, about 1064 nm, about 1070 nm, about1550 nm, about 2940 nm or about 10600 nm may be radiated. In anotherexample, laser electromagnetic wave having a wavelength in infrared ray(IR) region may be radiated.

In addition, specific conditions at the time of radiating the laserelectromagnetic wave may be controlled or changed depending on kinds ofthe resin, physical properties, thickness, of the polymer resinsubstrate, kinds or thickness of the metal layer to be formed, orappropriate level of adhesion in consideration of the above-mentionedfactors. Meanwhile, the laser electromagnetic wave may be radiated underradiation condition that an average power is about 0.1 to 50 W, or about1 to 30 W, or about 5 to 25 W, so that the polymer resin substrate ofthe first region has a predetermined surface roughness as describedabove.

In addition, the radiating of the laser electromagnetic wave may beradiated once by a relatively high power, but the laser electromagneticwave may be radiated two or more times by a relatively low power. As thenumber of radiating the laser electromagnetic wave is increased, thesurface roughness is increased, structures such as concavo-convex, andthe like, formed on the surface may be changed from hole shaped patternsto mesh patterned or amorphous surface structures. Therefore, bycontrolling the condition and the number of radiating the laserelectromagnetic wave, appropriate surface structure may be formed on thepolymer resin substrate of the first region, and the surface roughnesshaving an appropriate degree and excellent adhesion with the metal layermay be provided.

In addition, at the time of radiating the laser electromagnetic wave,radiation trace of the electromagnetic wave may be formed in a holeshape on the polymer resin substrate depending on an radiation intervalat the time of radiating the laser electromagnetic wave. However, inorder that the polymer resin substrate of the first region has theabove-mentioned appropriate surface roughness, it is preferred that thelaser electromagnetic wave may be radiated so that an interval betweencentral parts of radiation trace of the electromagnetic wave, or anradiation interval of the electromagnetic wave is about 20 μm or more,or about 20 to 70 μm, but is not particularly limited thereto. As aresult, the polymer resin substrate of the first region may haveappropriate surface roughness and appropriate adhesion between thepolymer resin substrate and the metal layer.

Meanwhile, as described above, after radiating the electromagnetic wavesuch as laser, or the like, on the first region, a conductive seed maybe formed on the polymer resin substrate as shown in {circle around (3)}of FIG. 1. The conductive seed is grown on the polymer resin substrateat the time of plating, and promotes formation of the metal layer by theplating. Accordingly, more excellent metal layer and the conductivepatterns may be appropriately formed on the polymer resin substrate ofthe first region.

The conductive seed may contain metal nanoparticles, metal ions, ormetal complex ions. In addition, the metal ion or the metal complex ionmay be used as ion itself or as metal-containing compounds to which themetal ions are coupled or as metal complexes containing metal complexions, or even as particles of the metal-containing compounds or themetal complexes.

The kind of the metal atoms included in the conductive seed is notparticularly limited as long as the metal atom has conductivity. Forexample, the conductive seed may include at least one kind metalselected from the group consisting of copper (Cu), platinum (Pt),palladium (Pd), silver (Ag), gold (Au), nickel (Ni), tungsten (W),titanium (Ti), chromium (Cr), aluminum (Al), zinc (Zn), tin (Sn), lead(Pb), magnesium (Mg), manganese (Mn) and iron (Fe), ions or complex ionsthereof.

In addition, in order to form the conductive seed on the polymer resinsubstrate, the conductive seed, a dispersion liquid or solutioncontaining the above-mentioned conductive seed such as the metalnanoparticles, the metal ions, or the metal complex ions may be appliedon the polymer resin substrate, followed by methods such as aprecipitating method, a drying method, and/or a reducing method, tothereby form the conductive seed in a particle form. More specifically,when the dispersion liquid, or the like, contains the metalnanoparticles, the metal nanoparticles are precipitated by difference insolubility and dried to form the conductive seed in a particle form, andwhen the dispersion liquid, or the like, contains the metal ions, or themetal complex ions (or the metal compounds or the complexes containingthese ions; for example, the metal compounds or the complexes such asAgNO₃, Ag₂SO₄, KAg(CN)₂), the metal ions, or the metal complex ions arereduced and dried to appropriately form the conductive seed in aparticle form.

Here, the reducing of the metal ion or the metal complex ion may beperformed by using general reducing agents, for example, at least onekind reducing agent selected from the group consisting of analcohol-based reducing agent, an aldehyde-based reducing agent,hypophosphorous acid-based reducing agent such as hypophosphorous acidsodium or hydrates thereof, or the like, hydrazine-based reducing agentsuch as hydrazine or hydrates thereof, or the like, sodium borohydrideand lithium aluminum hydride.

In addition, the dispersion liquid or the solution may appropriatelyinclude an aqueous-based polymer solution (for example, solutioncontaining polyvinylpyrrolidone-based polymer, and the like) capable ofimproving close adhesion between the polymer resin substrate and theconductive seed, or an aqueous-based complexing agent (for example, NH₃,EDTA, Rochelle salt, or the like) capable of stabilizing the metal ionsor the metal complex ions, as a liquid-phase medium.

Further, the dispersion liquid or the solution of the conductive seedmay be applied by general processes for applying a liquid-phasecomposition to the polymer resin substrate, for example, methods such asdipping, spin coating, spraying, and the like.

The conductive seed formed as described above may be formed on theentire surface of the polymer resin substrate including space betweenthe surface concavo-convex, patterns, or surface structures formed onthe first region, and may serve to promote favorable formation of themetal layer in the plating process and to control plating rate orphysical properties of the metal layer.

Meanwhile, right after the radiating of the electromagnetic wave asdescribed above, the process of forming the conductive seed isimmediately performed; however, after the polymer resin substrate isselectively surface-treated with a surfactant having a surface tensionlower than that of the dispersion liquid or solution, the process offorming the conductive seed may be performed. In addition, the polymerresin substrate may be surface-treated in a state in which thesurfactant is added to the dispersion liquid or the solution itself forforming the conductive seed. Here, the surfactant may have surfacetension lower than that of the dispersion liquid or the solution beforethe surfactant is added.

The surfactant may allow the conductive seed to be more uniformly formedand maintained on the surface of the polymer resin substrate, inparticular, between the surface concavo-convex, patterns, or surfacestructures. The reason is because the surfactant removes air between thesurface structures to assist the conductive seed in being easilypermeated between the surface structures. Therefore, when the treatmentwith the surfactant is added, the conductive seed is favorably absorbedentirely onto the first region, and the metal layer may be moreuniformly and favorably formed by the plating process. In addition, dueto the treatment with the surfactant and the formation of the conductiveseed, adhesion between the metal layer and the polymer resin substrateon the first region may be more improved to favorably form theconductive patterns having excellent conductivity.

Kinds of the surfactant may differ depending on kinds of the dispersionliquid or the solution of the conductive seed as described above, andmay include any liquid phase medium having surface tension lower thanthat of the dispersion liquid or the solution. For example, organicsolvents such as ethanol, and the like, having relatively low surfacetension may be used as the surfactant.

In addition, the surfactant may be treated by a method of immersing thepolymer resin substrate for several seconds to several minutes, and thelike.

Meanwhile, referring to {circle around (4)} of FIG. 1, after theconductive seed is formed on the polymer resin substrate, the metallayer may be formed by plating the polymer resin substrate having theconductive seed formed thereon. The process of forming the metal layermay be performed by electroless-plating the conductive metal on thepolymer resin substrate, and methods and conditions of performing theelectroless-plating process may be conducted by general methods andconditions.

For example, the plating process is performed by using a platingsolution containing conductive metals consisting of the metal layer, forexample, metal sources such as copper, and the like, complexing agents,pH adjustors, reducing agent, and the like, to form the metal layer onthe polymer resin substrate including the first region and the secondregion. Here, the metal layer may be formed on the grown conductive seedas described above.

The metal layer may be favorably formed on the first region by excellentadhesion; meanwhile, the metal layer may be easily removed from thesecond region due to poor adhesion to the polymer resin substrate (forexample, as shown in second photograph of FIG. 2a , the metal layer maybe delaminated from the polymer resin substrate).

After the metal layer is formed, the conductive seed and the metal layermay be selectively removed from the second region of the polymer resinsubstrate to form the conductive patterns on the remaining first regionas shown in {circle around (5)} and {circle around (6)} of FIG. 1.

As described above, since the metal layer is formed on the second regionin a state in which it is significantly easy to remove the metal layer,the metal layer and the conductive seed may be selectively removed fromthe second region by simple methods such as applying weak physical powerto the polymer resin substrate, and the like. Here, due to excellentadhesion between the metal layer and the polymer resin substrate on thefirst region, the metal layer may remain to form the conductivepatterns.

As described above, the process of removing the conductive seed and themetal layer from the second region, may be performed by any method ofapplying weak physical power onto the polymer resin substrate such asultrasonic radiation (sonication), liquid phase washing, liquid phaserinsing, air blowing, taping, brushing, and methods of using a manpowersuch as directly dusting or wiping with hands, or by a combination oftwo or more method(s) selected therefrom.

For example, washing or rinsing is performed in water under theultrasonic radiation for a predetermined time, and air blowing, and thelike, are performed, such that the conductive seed and the metal layerof the second region may be selectively removed.

The resin structure having the conductive pattern formed by theabove-described method may include the polymer resin substrate dividedinto the first region formed to have a surface roughness defined by acenter line arithmetic average roughness of the absolute values (Ra) ofabout 500 nm or more and the second region having a surface roughnesssmaller than that of the first region; and the conductive seed and themetal layer selectively formed on the first region of the polymer resinsubstrate.

Here, since the surface roughness of the first and second regions issufficiently described in the method according to an exemplaryembodiment, additional description thereof will be omitted. In addition,as described above, the first region may correspond to a region in whichthe electromagnetic wave such as laser, or the like, is radiated.

The resin structure as described above may be various kinds of resinproducts or resin layers such as a smart phone case, and the like,having conductive patterns for antenna, or may be various kinds of resinproducts or resin layers having conductive patterns such as other RFIDtags, various kinds of sensors, or MEMS structures, and the like.

As described above, according to the present invention, even though highpriced and specific inorganic additives such as CuCr₂O₄ having a spinelstructure, and the like, are not contained in a polymer resin substrateitself, surface roughness and adhesion to a metal layer, of a region inwhich conductive patterns are formed by radiating an electromagneticwave such as laser, or the like, may be adjusted, such that theconductive patterns may be formed on the polymer resin substrate by asimplified process

Therefore, the manufacturing cost of the process of forming theconductive patterns and the cost of raw materials may be decreased, anddeterioration of physical properties such as mechanical properties, andthe like, of the polymer resin substrate or products caused by thespecific inorganic additive, may be minimized. In addition, sincedesirable fine conductive patterns may be formed on the polymer resinsubstrate without using the specific inorganic additive, colors of theresin itself may be clearly shown, and it is easy to implement colors ofthe polymer resin substrate or products to be desirable colors.Therefore, according to exemplary embodiments of the present invention,fine conductive patterns may be formed on various kinds of resinproducts or resin layers at lower manufacturing cost and by a simplifiedprocess, such that resin products having various colors and shapes,including new resin products which have not been suggested before, maybe implemented.

Hereinafter, action and effects of the present invention are describedby specific examples of the present invention in detail. Meanwhile,these examples are provided by way of example, and therefore, should notbe construed as limiting the scope of the present invention.

Example 1 Formation of Conductive Patterns by Laser Direct Radiation

A polycarbonate resin substrate containing an UV stabilizer, a thermalstabilizer, and an impact reinforcing agent having a total amount ofless than 2 wt %, without containing other different inorganic additiveswas prepared. Laser having a wavelength of 1064 nm was radiated onceonto a predetermined region of the polycarbonate resin substrate underradiation condition having an average power of 21.4 W. Here, theinterval between central parts of the laser radiation trace of thepolycarbonate resin was controlled to be about 35 μm by controlling theradiation interval of the laser.

Accordingly, the polycarbonate resin substrate radiated by the laser hada predetermined surface roughness on the predetermined region. Aphotograph of the polycarbonate resin substrate as manufactured abovewas shown in the first photograph of FIG. 2a , and an optical microscopephotograph of the region radiated by laser formed so as to have thesurface roughness was shown in FIG. 2 b.

Then, the polycarbonate resin substrate was immersed into an aqueoussolution including Pd ions for about 5 minutes, to form a conductiveseed including Pd on the substrate. Next, the substrate was washed withdeionized water, and an elelctroless-plating was performed by usingcopper as a conductive metal. At the time of the electroless-plating, aplating solution containing copper source (copper sulfate), a complexingagent (Rochelle salt), a pH adjustor (sodium hydroxide aqueoussolution), and a reducing agent (formaldehyde), was used. Theelectroless-plating was performed at room temperature for about 1 hourto form the metal layer.

A photograph showing the metal layer formed as described above was shownin the second photograph of FIG. 2a . Referring to FIG. 2a , it could beconfirmed that the metal layer was favorably formed in the regionradiated the laser; however, the metal layer in the remaining region wasformed in a delamination state due to poor adhesion to be significantlyeasily removed.

Then, the substrate was immersed into the deionized water, followed byultrasonic radiation (sonication) for 20 minutes, and air blowing, toselectively remove the metal layer of the region which is not radiatedby laser. The third photograph of FIG. 2a is a photograph showing astate in which the metal layer, and the like, are selectively removedfrom the region which is not radiated by laser, to form conductivepatterns on the substrate, and FIG. 2c is a scanning electron microscope(SEM) photograph showing a portion in which the conductive patterns areformed. Referring to FIG. 2c , it could be confirmed that the conductiveseed was grown in the corresponding portion, and the metal layer wasformed on the conductive sheet (conductive metal particles) by plating.

Examples 2 to 8 Formation of Conductive Patterns by Laser DirectRadiation

Resin structures of Examples 2 to 8 each having conductive patterns weremanufactured by the same method as Example 1 except that the radiationcondition of the average power of laser and the interval between centralparts of radiation trace of laser in Example 1 are changed into about15.7 W and about 25 μm (Example 2), about 15.7 W and about 35 μm(Example 3), about 18.6 W and about 45 μm (Example 4), about 21.4 W andabout 45 μm (Example 5), about 21.4 W and about 55 μm (Example 6), about24.2 W and about 55 μm (Example 7), about 28.5 W and about 55 μm(Example 8) in once radiation.

Example 9 Formation of Conductive Patterns by Laser Direct Radiation

Resin structure of Example 9 having conductive patterns was manufacturedby the same method as Example 1 except that a mixture of ethanol and anaqueous-based complex ion solution (solution containing AgNO₃ and NH₃which is a complexing agent) containing Ag complex ions instead of Pdwas used as a solution for forming the conductive seed. FIG. 3 is aphotograph showing a state in which the conductive patterns were formedon the substrate by selectively removing the metal layer, and the like,from the region which is not radiated by laser.

Test Example 1 Evaluation of Surface Roughness of Conductive Patterns

Surface roughness was measured on predetermined regions of thepolycarbonate resin substrate radiated by laser according to Examples 1to 9. The center line arithmetic average roughness of the absolutevalues (Ra) of an area of 0.2 mm×0.3 mm was measured by using an opticalprofiler (Nano view E1000, Nanosystem, Korea). In FIG. 4a , color changedepending on height was shown by using optical profiler in the regionradiated by laser of Example 6 (left), and a photograph implementing thecolor change in three dimensional structure was shown (right). Inaddition, the measured surface roughness were also shown in FIG. 4a .FIG. 4b is a photograph showing Example 8 and shows change of surfacestate depending on change of the laser condition and changed values ofsurface roughness, respectively. Ra values obtained by measuring surfaceroughness at different six points of the region radiated by laser inExamples 1 to 9 using the above-described methods and averaging themeasured values were summarized and shown in the following Table 1. Forreference, FIGS. 4a and 4b show surface roughness measured at any onepoint among six points, and Table. 1 shows an average value of thevalues measured at six points.

Test Example 2 Evaluation of Adhesion of Conductive Patterns

A cross-cut test was conducted by using a tape having adhesion of 4.0 to6.0N/10 mm width according to ISO 2409 standard method (3M scotch tape#371) in the region having the metal layer and the conductive patternsaccording to Examples 1 to 9 formed thereon. Here, adhesion or closeadhesion between the substrate and the metal layer was tested by cuttingthe metal layer to be 10×10 graph (an interval of about 2 mm or less),and measuring area of the metal layer delaminated by attaching anddetaching the tape.

Evaluation on adhesion of the delamination area of the conductivepatterns was conducted under the following ISO class standard.

1. class 0: When the delamination area of the conductive patternscorresponds to 0% of area of target conductive patterns underevaluation.

2. class 1: When the delamination area of the conductive patternscorresponds to more than 0% to 5% or less of area of target conductivepatterns under evaluation.

3. class 2: When the delamination area of the conductive patternscorresponds to more than 5% to 15% or less of area of target conductivepatterns under evaluation.

4. class 3: When the delamination area of the conductive patternscorresponds to more than 15% to 35% or less of area of target conductivepatterns under evaluation.

5. class 4: When the delamination area of the conductive patternscorresponds to more than 35% to 65% or less of area of target conductivepatterns under evaluation.

6. class 5: When the delamination area of the conductive patternscorresponds to more than 65% of area of target conductive patterns underevaluation.

In addition, uniformity of the metal layer (conductive patterns) afterthe conductive patterns were formed in Examples 1 to 9 was evaluatedunder the following standards.

1. ◯: With the unaided eye, uniformly colored metal layer (plated thinfilm) is formed in all regions having surface roughness formed by laserradiation, and when observing the surface of the metal layer by opticalmicroscopy, pores are not shown.

2. Δ: With the unaided eye, uniformly colored metal layer (plated thinfilm) is formed in all regions having surface roughness formed by laserradiation; however, when observing the surface of the metal layer byoptical microscopy, pores are partially shown.

3. X: With the unaided eye, uniformly colored metal layer (plated thinfilm) is not formed in all regions having surface roughness formed bylaser radiation; and when observing the surface of the metal layer byoptical microscopy, pores are partially shown at least.

Evaluation results were shown in the following Table 1.

TABLE 1 Interval (μm) Between Main Central Component Evaluation Parts ofof on Average Laser Conductive Uniformity of Power of Radiation AverageRa ISO 2409 Seed Metal Layer Laser (W) Trace (nm) class Example 1 Pd ∘21.4 35 1110 0 Example 2 Pd ∘ 15.7 25 645 0 Example 3 Pd Δ 15.7 35 710 1Example 4 Pd ∘ 18.6 45 705 1 Example 5 Pd ∘ 21.4 45 818 1 Example 6 Pd ∘21.4 55 837 1 Example 7 Pd ∘ 24.2 55 1275 0 Example 8 Pd ∘ 28.5 55 34700 Example 9 Ag ∘ 21.4 35 1110 0

Referring to Table 1, it could be confirmed that in Examples 1 to 9,significantly excellent metal layer (conductive patterns) could beselectively formed in the region radiated by laser, through the methodincluding the process of forming surface roughness (Ra) of about 500 nmor more in the region radiated by laser to improve adhesion between thepolymer resin substrate and the metal layer, and the process of formingthe conductive seed, and the like. In particular, it could be confirmedthat the conductive pattern has excellent uniformity and excellentadhesion to the polymer resin substrate, thereby being favorably formed.

In conclusion, according to Examples above, even though high priced andspecific inorganic additives such as CuCr₂O₄, and the like, are notcontained in the polymer resin substrate itself, surface roughness ofthe region in which conductive patterns are formed by radiating anelectromagnetic wave such as laser, and the like, and adhesion to ametal layer, may be adjusted, such that the conductive patterns may beformed on the polymer resin substrate by a simplified process.

1. A method for forming conductive pattern by direct radiation of anelectromagnetic wave, the method comprising: forming a first regionhaving a predetermined surface roughness by selectively radiating theelectromagnetic wave on a polymer resin substrate; forming a conductiveseed on the polymer resin substrate; forming a metal layer by platingthe polymer resin substrate having the conductive seed formed thereon;and removing the conductive seed and the metal layer from a secondregion of the polymer resin substrate, wherein the second region hassurface roughness smaller than that of the first region.
 2. The methodof claim 1, wherein the first region of the polymer resin substrate hassurface roughness defined by a center line arithmetic average roughnessof the absolute values (Ra) of 500 nm or more, and the second region hasa center line arithmetic average roughness of the absolute values (Ra)smaller than that of the first region.
 3. The method of claim 1, whereinwhen a cross-cut test having an interval of 2 mm or less according toISO 2409 standard method is conducted by using a tape having adhesion of4.0 to 6.0N/10 mm width, the first region of the polymer resin substratehas surface roughness defined by adhesion at which a delamination areaof a target metal layer under test corresponds to 5% or less of an areaof the metal layer.
 4. The method of claim 1, wherein when a cross-cuttest having an interval of 2 mm or less according to ISO 2409 standardmethod is conducted by using a tape having adhesion of 4.0 to 6.0N/10 mmwidth, the second region of the polymer resin substrate has surfaceroughness defined by adhesion at which a delamination area of a targetmetal layer under test corresponds to 65% or more of an area of themetal layer.
 5. The method of claim 1, wherein the polymer resinsubstrate contains a thermosetting resin or a thermoplastic resin. 6.The method of claim 5, wherein the polymer resin substrate contains atleast one kind selected from the group consisting of an ABS resin, apolyalkylene terephthalate resin, a polycarbonate resin, a polypropyleneresin, and a polyphthalamide resin.
 7. The method of claim 1, whereinthe radiating of the electromagnetic wave is performed by radiating alaser electromagnetic wave having a wavelength of 248 nm, 308 nm, 355nm, 532 nm, 585 nm, 755 nm, 1064 nm, 1070 nm, 1550 nm, 2940 nm or 10600nm.
 8. The method of claim 1, wherein the radiating of theelectromagnetic wave is performed by radiating a laser electromagneticwave under radiation condition having 0.1 to 50 W of an average power.9. The method of claim 1, wherein the radiating of the electromagneticwave is performed by radiating a laser electromagnetic wave so that aninterval between central parts of radiation trace of the electromagneticwave shown on the polymer resin substrate is 20 to 70 μm.
 10. The methodof claim 1, wherein the radiating of the electromagnetic wave isperformed by radiating a laser electromagnetic wave once or by radiatingthe laser electromagnetic wave two or more times.
 11. The method ofclaim 1, wherein the conductive seed contains metal nanoparticles, metalions, or metal complex ions.
 12. The method of claim 11, wherein theconductive seed contains at least one kind metal selected from the groupconsisting of copper (Cu), platinum (Pt), palladium (Pd), silver (Ag),gold (Au), nickel (Ni), tungsten (W), titanium (Ti), chromium (Cr),aluminum (Al), zinc (Zn), tin (Sn), lead (Pb), magnesium (Mg), manganese(Mn) and iron (Fe), ions or complex ions thereof.
 13. The method ofclaim 11, wherein the forming of the conductive seed includes: applyinga dispersion liquid or solution containing the metal nanoparticles, themetal ions, or the metal complex ions on the polymer resin substrate;and precipitating and drying the metal nanoparticles or reducing anddrying the metal ions or the metal complex ions to form the conductiveseed in a particle form.
 14. The method of claim 13, wherein thereducing of the metal ions or the metal complex ions is performed in thepresence of at least one kind reducing agent selected from the groupconsisting of an alcohol-based reducing agent, an aldehyde-basedreducing agent, a hypophosphite-based reducing agent, a hydrazine-basedreducing agent, sodium borohydride and lithium aluminum hydride.
 15. Themethod of claim 13, further comprising: adding a surfactant havingsurface tension lower than that of the dispersion liquid or the solutionin the forming of the conductive seed, or surface-treating the polymerresin substrate with a surfactant having surface tension lower than thatof the dispersion liquid or solution, between the radiating of theelectromagnetic wave and the forming of the conductive seed.
 16. Themethod of claim 1, wherein the forming of the metal layer includeselectroless-plating a conductive metal on the polymer resin substrate.17. The method of claim 1, wherein the removing of the conductive seedand the metal layer from the second region includes applying physicalpower onto the polymer resin substrate by combination of one or two ormore method(s) selected from the group consisting of ultrasonicradiation (sonication), liquid phase washing, liquid phase rinsing, airblowing, taping, brushing, and a method of using a manpower.
 18. A resinstructure having conductive pattern comprising: a polymer resinsubstrate including a first region formed to have a predeterminedsurface roughness and a second region having surface roughness smallerthan that of the first region; and a conductive seed and a metal layerselectively formed on the first region of the polymer resin substrate.19. The resin structure of claim 18, wherein the first regioncorresponds to a region radiated by the electromagnetic wave.
 20. Theresin structure of claim 18, wherein the first region of the polymerresin substrate has surface roughness defined by a center linearithmetic average roughness of the absolute values (Ra) of 500 nm ormore, and the second region has a center line arithmetic averageroughness of the absolute values (Ra) smaller than that of the firstregion.
 21. The resin structure of claim 18, wherein when a cross-cuttest having an interval of 2 mm or less according to ISO 2409 standardmethod is conducted by using a tape having adhesion of 4.0 to 6.0N/10 mmwidth, the first region of the polymer resin substrate has surfaceroughness defined by adhesion at which a delamination area of a targetmetal layer under test corresponds to 5% or less of an area of the metallayer.
 22. The resin structure of claim 18, wherein when a cross-cuttest having an interval of 2 mm or less according to ISO 2409 standardmethod is conducted by using a tape having adhesion of 4.0 to 6.0N/10 mmwidth, the second region of the polymer resin substrate has surfaceroughness defined by adhesion at which a delamination area of a targetmetal layer under test corresponds to 65% or more of an area of themetal layer.